• Title, Summary, Keyword: ATP

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Disruption of ATP binding destabilizes NPM/B23 and inhibits anti-apoptotic function

  • Choi, Joung-Woo;Lee, Sang-Bae;Ahn, Jee-Yin;Lee, Kyung-Hoon
    • BMB Reports
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    • v.41 no.12
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    • pp.840-845
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    • 2008
  • Nucleophosmin/B23, a major nucleolar phosphoprotein, is overexpressed in actively proliferating cells. In this study, we demonstrate that B23 exclusively localizes in the nucleolus, whereas ATP depletion results in the redistribution of B23 throughout the whole nucleus and destabilizes B23 via caspase-3 mediated cleavage. Interestingly, ATP binding precedes PI(3,4,5)P3 binding at lysine 263 and ATP binding mutants fail to restore the anti-apoptotic functions of B23 in PC12 cells. Thus, the ATP-B23 interaction is required for the stability of the B23 protein and regulates cell survival, confining B23 within the nucleolus in PC12 cells.

The Study of ATP Onboard System Interface for Tilting Train (틸팅열차용 ATP 차상장치의 인터페이스 연구)

  • Baek, Jong-Hyen;Kim, Yong-Kyu
    • Proceedings of the KIEE Conference
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    • pp.184-186
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    • 2008
  • 경부고속철도의 개통과 함께 서울-부산 간 운행시간이 새마을호 기준 4시간 30분에서 2시간으로 단축되는 등 획기적인 시간 절감을 이루었으나 이는 고속철도가 운행되는 지역에 국한된 것이다. 이에 고속철도 비 수혜지역의 운행시간 단축을 위해 기존선 속도향상이 요구되며, 이러한 목적으로 한국철도기술연구원에서는 틸팅열차를 개발하여 시운전 10만Km를 목표로 시험운행중이다. 또한 한국철도공사에서는 이와 유사한 목적으로 기존선 신호시스템인 ATS 시스템을 차상신호시스템(ATP)으로 개량하는 사업이 추진되고 있다. 현재 틸팅열차에는 기존의 ATS(자동열차정지장치) 차상장치만을 장착하여 차량의 성능 확인을 위한 시험 및 시운전을 우선적으로 추진하고 있는 상태이며 이러한 ATS 차상장치는 160km/h 이하의 속도에서만 본연의 기능이 유지되고, 그 이상의 속도에서는 현실적으로 사용이 어렵기 때문에 틸팅열차의 목표속도인 200km/h에서 적합하게 시험하기 위해서는 적합하지 않다. 따라서 한국철도공사에서 추진하고 있는 ATP 구축사업의 지상설비와 연계될 수 있는 ATP 차상장치를 설치하여 시험을 하여야 한다. 본 논문에서는 이를 위한 틸팅열차와 ATP 차상장치와의 인터페이스에 대해 연구하였다.

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Thiol-dependent Redox Mechanisms in the Modification of ATP-Sensitive Potassium Channels in Rabbit Ventricular Myocytes

  • Han, Jin;Kim, Na-Ri;Cuong, Dang-Van;Kim, Chung-Hui;Kim, Eui-Yong
    • The Korean Journal of Physiology and Pharmacology
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    • v.7 no.1
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    • pp.15-23
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    • 2003
  • Cellular redox state is known to be perturbed during ischemia and that $Ca^{2+}$ and $K^2$ channels have been shown to have functional thiol groups. In this study, the properties of thiol redox modulation of the ATP-sensitive $K^2$ ($K_{ATP}$) channel were examined in rabbit ventricular myocytes. Rabbit ventricular myocytes were isolated using a Langendorff column for coronary perfusion and collagenase. Single-channel currents were measured in excised membrane patch configuration of patch-clamp technique. The thiol oxidizing agent 5,5'-dithio-bis-(2-nitro-benzoic acid) (DTNB) inhibited the channel activity, and the inhibitory effect of DTNB was reversed by dithiothreitol (disulfide reducing agent; DTT). DTT itself did not have any effect on the channel activity. However, in the patches excised from the metabolically compromised cells, DTT increased the channel activity. DTT had no effect on the inhibitory action by ATP, showing that thiol oxidation was not involved in the blocking mechanism of ATP. There were no statistical difference in the single channel conductance for the oxidized and reduced states of the channel. Analysis of the open and closed time distributions showed that DTNB had no effect on open and closed time distributions shorter than 4 ms. On the other hand, DTNB decreased the life time of bursts and increased the interburst interval. N-ethylmaleimide (NEM), a substance that reacts with thiol groups of cystein residues in proteins, induced irreversible closure of the channel. The thiol oxidizing agents (DTNB, NEM) inhibited of the $K_{ATP}$ channel only, when added to the cytoplasmic side. The results suggested that metabolism-induced changes in the thiol redox can also modulate $K_{ATP}$ channel activity and that a modulatory site of thiol redox may be located on the cytoplasmic side of the $K_{ATP}$ channel in rabbit ventricular myocytes.

Enhancement of ATP-induced Currents by Phospholipase D1 Overexpressed in PC12 Cells

  • Park, Jin-Bong;Kim, Young-Rae;Jeon, Byeong-Hwa;Park, Seung-Kiel;Oh, Sae-Ock;Kim, Young-Geun;Lee, Sang-Do;Kim, Kwang-Jin
    • The Korean Journal of Physiology and Pharmacology
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    • v.7 no.4
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    • pp.223-229
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    • 2003
  • Using phospholipase D1 (PLD1)-overexpressing PC12 (PLD1-PC12) cells, the regulatory roles of PLD1 on ATP-induced currents were investigated. In control and PLD1-PC12 cells, ATP increased PLD activity in an external $Ca^{2+}$ dependent manner. PLD activity stimulated by ATP was substantially larger in PLD1-PC12 cells than in control cells. In whole-cell voltage-clamp mode, ATP induced transient inward and outward currents. The outward currents inhibited by TEA or charybdotoxin were significantly larger in PLD1-PC12 cells than in control cells. The inward currents known as $Ca^{2+}$ permeable nonselective cation currents were also larger in PLD1-PC12 cells than in control cells. However, the difference between the two groups of cells disappeared in $Ca^{2+}$-free external solution, where ATP did not activate PLD. Finally, ATP-induced $^{45}Ca$ uptakes were also larger in PLD1-PC12 cells than in control cells. These results suggest that PLD enhances ATP-induced $Ca^{2+}$ influx via $Ca^{2+}$ permeable nonselective cation channels and increases subsequent $Ca^{2+}$-activated $K^+$ currents in PC12 cells.

Deletion of cg1360 Affects ATP Synthase Function and Enhances Production of L-Valine in Corynebacterium glutamicum

  • Wang, Xiaochen;Yang, Hongyu;Zhou, Wei;Liu, Jun;Xu, Ning
    • Journal of Microbiology and Biotechnology
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    • v.29 no.8
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    • pp.1288-1298
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    • 2019
  • Bacterial ATP synthases drive ATP synthesis by a rotary mechanism, and play a vital role in physiology and cell metabolism. Corynebacterium glutamicum is well known as an industrial workhorse for amino acid production, and its ATP synthase operon contains eight structural genes and two adjacent genes, cg1360 and cg1361. So far, the physiological functions of Cg1360 (GenBank CAF19908) and Cg1361 (GenBank CAF19909) remain unclear. Here, we showed that Cg1360 was a hydrophobic protein with four transmembrane helices (TMHs), while no TMH was found in Cg1361. Deletion of cg1360, but not cg1361, led to significantly reduced cell growth using glucose and acetic acid as carbon sources, reduced F1 portions in the membrane, reduced ATP-driven proton-pumping activity and ATPase activity, suggesting that Cg1360 plays an important role in ATP synthase function. The intracellular ATP concentration in the ${\Delta}cg1360$ mutant was decreased to 72% of the wild type, while the NADH and NADPH levels in the ${\Delta}cg1360$ mutant were increased by 29% and 26%, respectively. However, the ${\Delta}cg1361$ mutant exhibited comparable intracellular ATP, NADH and NADPH levels with the wild-type strain. Moreover, the effect of cg1360 deletion on L-valine production was examined in the L-valine-producing V-10 strain. The final production of L-valine in the $V-10-{\Delta}cg1360$ mutant reached $9.2{\pm}0.3g/l$ in shake flasks, which was 14% higher than that of the V-10 strain. Thus, Cg1360 can be used as an effective engineering target by altering energy metabolism for the enhancement of amino acid production in C. glutamicum.

Stability and Characterization of the ATP-dependent Clp Protease from Escherichia coli (Excherichia coli 에 존재하는 ATP -의존성 Clp 효소의 안정성 및 특성)

  • ;Michael R. Maurizi
    • Korean Journal of Microbiology
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    • v.30 no.6
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    • pp.528-532
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    • 1992
  • The ATP-dependent protease. Clp P from Esehaichia coli has been increase the stahility with or without detergent as Triton X-100 and NP-40 in the Clp P. The C]p P proteolytic activity was remained to 0.1 M salt by $Na^{-1}$, $K^{+}$, $Li^{+}$ but was inhihited by $SO_4^{2}$. An active ATPase site in Clp A is required for A TP-dependent proteolysis by Clp protease as

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In Vitro Adenosine Triphosphate Based Chemotherapy Response Assay in Gastric Cancer

  • Park, Seul-Kee;Woo, Yang-Hee;Kim, Ho-Geun;Lee, Yong-Chan;Choi, Sung-Ho;Hyung, Woo-Jin;Noh, Sung-Hoon
    • Journal of Gastric Cancer
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    • v.10 no.4
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    • pp.155-161
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    • 2010
  • Purpose: The purpose of this study was to investigate the reliability and the clinical applicability of the adenosine-triphosphate-based chemotherapy response assay (ATP-CRA) as a method of determining in vitro chemosensitivity in patients with gastric cancer. Materials and Methods: A total of 243 gastric cancer tissue samples were obtained from gastrectomies performed between February 2007 and January 2010. We evaluated the effectiveness of the ATP-CRA assay in determining the chemosensitivity of gastric cancer specimens using eleven chemotherapeutic agents - etoposide, doxorubicin, epirubicin, mytomicin, 5-fluorouracil, oxaliplatin, irinotecan, docetaxel, paclitaxel, methotraxate, and cisplatin - for chemosensitivity studies using ATP-CRA. We assessed the failure rate, the cell death rate, and the chemosensitivity index. Results: The failure rate of ATP-CRA was 1.6% (4/243). The mean coefficient of variation for triplicate ATP measurements was 6.5%. Etoposide showed the highest cell death rate (35.9%) while methotrexate showed the lowest (16.6%). The most active chemotherapeutic agent was etoposide, which most frequently ranked highest in the chemosensitivity test: 31.9% (51/160). Oxaliplatin was more active against early gastric cancers than advanced gastric cancers, whereas docetaxel was more active against advanced cancers. The lymph node negative group showed a significantly higher cell death rate than the lymph node positive group when treated with doxorubicin, epirubicin, and mitomycin. Conclusions: ATP-CRA is a stable and clinically applicable in vitro chemosensitivity test with a low failure rate. The clinical usefulness of ATP-CRA should be evaluated by prospective studies comparing the regimen guided by ATP-CRA with an empirical regimen.

P2X7 Receptor-mediated Membrane Blebbing in Salivary Epithelial Cells

  • Hwang, Sung-Min;Koo, Na-Youn;Choi, Se-Young;Chun, Gae-Sig;Kim, Joong-Soo;Park, Kyung-Pyo
    • The Korean Journal of Physiology and Pharmacology
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    • v.13 no.3
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    • pp.175-179
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    • 2009
  • High concentrations of ATP induce membrane blebbing. However, the underlying mechanism involved in epithelial cells remains unclear. In this study, we investigated the role of the P2X7 receptor (P2X7R) in membrane blebbing using Par C5 cells. We stimulated the cells with 5 mM of ATP for 1${\sim}$2 hrs and found the characteristics of membrane blebbing, a hallmark of apoptotic cell death. In addition, 500 ${\mu}M$ Bz-ATP, a specific P2X7R agonist, induced membrane blebbing. However, 300 ${\mu}M$ of Ox-ATP, a P2X7R antagonist, inhibited ATP-induced membrane blebbing, suggesting that ATP-induced membrane blebbing is mediated by P2X7R. We found that ATP-induced membrane blebbing was mediated by ROCK I activation and MLC phosphorylation, but not by caspase-3. Five mM of ATP evoked a biphasic $[Ca^{2+}]_i$ response; a transient $[Ca^{2+}]_i$ peak and sustained $[Ca^{2+}]_i$ increase secondary to ATP-stimulated $Ca^{2+}$ influx. These results suggest that P2X7R plays a role in membrane blebbing of the salivary gland epithelial cells.

Action of Phospholipase $A_2$in Histamine Release from Mast Cells (비만세포에서 Histamine유리에 관여하는 Phospholipase $A_2$의 작용)

  • 이윤혜;이승준;서무현;장용운;윤정이
    • YAKHAK HOEJI
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    • v.45 no.3
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    • pp.287-292
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    • 2001
  • To investigate whether phospholipase $A_2$pathway is involved in histamine release of rat peritoneal mast cells, we measured histamine release in the presence of various enzyme inhibitors involved in eicosanoid pathway, such as phospholipase $A_2$, cyclooxygenase and lipoxygenase. Phospholipase $A_2$inhibitors, manoalide and OPC, significantly inhibited histamine release induced by 100 $\mu$M ATP and 1$\mu$g/ml compound 48/80. Cyclooxygenase inhibitors, ibuprofen and indomethacin, significantly inhibited ATP-induced histamine release and lipoxygenase inhibitors, baicalein and caffeic acid, also significantly inhibited. To investigate the involvement of protein kinase in ATP- and compound 48/80-induced histamine release, we observed effects of protein kinase inhibitors on histamine release. Bisindolmaleimide (protein kinase C antagonist) dose-dependently inhibited both ATP and compound 48/80-induced histamine release. Tyrosine kinase inhibitors (methyl 2,5-dihydroxy cinnamate and genistein) dose-dependently inhibited ATP and compound 48/80-induced histamine release. Protein kinase C and tyrosine kinase seem to be involved in histamine release induced by ATP and compound 48/80. These results suggest that phospholipase $A_2$pathway as well as protein kinase C and tyrosine kinase are involved in histamine release of rat peritoneal mast cells by ATP and compound 48/80.

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THE IMPORTANCE OF BICARBONATE-BUFFER ON CARDIAC FUNCTION: Contractility, Membrane Potentials and ATP Content of Isolated Atria in the Absence of External Buffers (심장기능(心臟機能)에 미치는 Bicarbonate-Buffer의 중요성(重要性) : Buffer 제거(除去)에 의(依)한 유리심방(遊離心房)의 수축성(收縮性), 막전위(膜電位) 및 ATP 함량(含量)의 변동(變動))

  • Ko, Kye-Chang;Han, Dae-Sup;Jung, Jee-Chang
    • The Korean Journal of Pharmacology
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    • v.8 no.2
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    • pp.63-69
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    • 1972
  • The effects of omission of buffers from Krebs-Ringer medium on contractile activity, membrane potentials and ATP content of electrically stimulated isolated rat atria were investigated. 1) Contractile status: A rapid and marked depression of the contractile activity of atria occurred when buffer-free medium was substituted for the normal Krebs-Ringer medium. 2) Electrical status: The omission of buffers from medium did not alter the resting or action potential magnitudes of atria. However, the action potential duration was on initial increase followed by a decrease in the buffer-free medium. 3) ATP concentration: The omission of buffers from medium resulted in a marked decrease in the ATP levels of atria. It has been also found in the present study that bicarbonate buffer plays an important role for the maintenance of the contractility and ATP levels of the heart. The contractile depression by the omission of buffers was not directly associated with electrical alterations in resting or action potentials of the heart. In the absence of bicarbonate-buffer, glucose no longer plays to maintain the contractile activity and the ATP levels of rat atria.

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